Boiler



P. G, KAISER Oct. 28, 1930.

BOILER 'Filed Sept. 13, 1926 3 Sheets-Sheet 2 W M A 79m diiorngw 5 Sheets-Sheet 3 P. G. KAISER Oct. 28, 1930.

BOILER Filed Sept. 13., 1926 i 2 a l 'Patented0ct.,28, 1930 I I i 1,779,939

I nNrrEo sm gr ori ice l BAUL G. KAISER, or cn caeo; ILLINOIS; 1201mm i Application fiiea September 13 19 2s. s rial no. 135,076.

My inventionrelates-to firer tube boilers, Figure '1 of these drawings is a vertical either heating or power generatingandhas elevation through a complete'boiler assembly for its object an increased capacity ma depos which may be considered as being taken on sible by amore rapid circulation of the Water the line 11 oi Figure 2 slightly to one side Within the boiler which permits a higher temof the axis or the boiler.

perature gradient between them and the Figure .2 is a transverse elevation taken on water, p I I the lines 22 of Figures 1 and 3; and V Another object of my invention is to pre- Figure 3 is a plan View taken on the lines vent the collection oi'sediment andscale on 3 of Figures 1 and 2. V i

. the heating surfaces, by the rapid circulation Figure l is a'vertical elevation through a of Water, f v i g complete boiler assembly which may be con- Another object of Qmyinvention is the sidered as being taken onthe line 4.f provision of a boiler in Whichfthefiretubes Figure -5 slightlyto 011 i of the aXiS 0f 1 r g t d 'in'- a plurality of groups the boiler, showing a preferredmodification through which the heated gas is passe'd'in ofmy invention applicableto existing boiler succession, thereby heating different sets of Str ctures. p

tubes to diflerenttemperatures,resulting in Figure 5 is a transverse front elevation differential rates of vapor production in diifshowing a section of the modificationtaken on ferent sections o'f'the' boiler and consequent he lui h- 0f ig re 4 g thermo-siphon circulation of the Working Figiu-o. is a transverse rear elevation fluid. I V i 7 showing a section of this modification taken It is also an important object of my inven-' 011 e li s 66 of Figure 4:: i V v 51011 to provide pater 0f bafies in om- Ill tl'lG disclosed in bination With such groups of fire tubes difier- 1 t0 ,*the Shell of the boiler 10 is in general entially heated to direct'and assist the flow of yli i l, u it has lateral Water g the water in convection currents resulting and front and rear Water legs 12 and 12 en from the unequal production of Water vapor Closing tlle'fire box 13. v v

bubbles adj acent the diilerentgroups of tubes. At h r flI end of the boiler all of the c A further important object of my invention fire tubes extend from a common front head 30 is to provide for the adaptation f the said 1 but at e fi tubes 011 the gh so i ti t i ti t pe f b il r with t hand do not extend as far as do those on the necessity of ext nsiv alt tio f the the lei"t,'but terminate inan auxiliaryrear present structure, thereby procuring the bened 15 om i an e inwardly from the ficial results above described in existing strucreal? head to Which eXteIld h fire tubes 35 tures at a minimum cost, j on'tllell'eft hand side-0f the boiler. In oper- 5 Briefly described, I secu'remy improved rel therefore: the Combustion" gases P sults by dividingthe fire tubes vertically into YQ dg l 17 aro nd therear end groups, the combustion gases passing through oitne crown sheet 18, forwardly through the these groups in series, and inusing a vertical fi b 1 t h right half of the boiler,

40 bafli i th t b tw e thesegroups f into the iorward smoke b02120, crossing over fir tube t tabli h; t i l ti f to the left and passing rearwardly through the Wateraround the b'aflle. Y the left side fire tubes 21 into the rear smoke The foregoing, and also other features'and box From the rear smoke box the comadvantages of my invention, ar set f rthi ".bustion gases pass through the bridging 23,

45 the following description of aheatingsystem and upwardly through the stack 24. It is boiler embodying my inventionand illusto be noted that the bridging 23 Whichforms trated inthe accompanying drawings. My the outlet opening for thecombustion gases invention can be incorporated in a highpresas they pass outirom the left hand tubes 21, sure cylinder boiler and many other types of is offset downwardly quite noticeably in 50 boilers, also in'existing boiler structures. reference to the left hand group of tubes,

as is shown in Fi 1. The purpose of this is to draw the com ustion gases downwardly so that some of the hot gases will pass through the lowermost tubes 21 also, thereby opposing the tendency of the combustion gases to pass through only the uppermost tubes of the roup. The effect of this drawing down 0% reflected in the right hand group of fire tubes 19 with the result that there also is a greater tendency for more of the hot gases to pass a through the lowermost tubes.

In general the gases passing than those passing through the left hand tubes 21. I prefer to take advantage of this fact by making the fire tubes 19 somewhat larger in diameter than the fire tubes 21, although making them fewer in number. The result I thereby secure is to make a considerably larger aggregate cross sectional area of the fire tube for the passage of combustion gases in the right hand tubes 19 as compared with the left hand tubes 21. But

. at the same time the aggregate heat transfer area-that is, the total outside circumferential areas of the tubes-is less in the case of the right hand tubes 19 than in the case of the left hand tubes 21. This relation between the two groups of tubes is advantageous because the gases passing through the righthand tubes 19 are considerably hotter than the relatively spent gases passing through the left hand tubes 21. This re-' quires less heat transfer area on the right hand tubes than on the left hand tubes. Also the gases being hotter in the right hand tubes than in the left hand tubes they should have a larger aggregate cross sectional area in the right hand tubes than in the left hand tubes to compensate for contraction in cool- In practice, I prefer to accentuate this relation, and in the drawings I have shown the left hand tubes 21 as being considerably longerthan the right hand tubes 19 so that the aggregate exterior area of the left hand tubes is made greater by the increased length notwithstanding, of course, that the volume of theleft hand tubes 21 is made greater by the increased length of the tubes.

In other words, if I make the tubes on both sides of the same length, I secure this advantageous relation between heat transfer .1 areas and fire tube cross sectional areas; and

if I make the left hand tubes longer than the right hand tubes, I can accentuate the advantages of this relation by adding to the aggregate or sum total exterior areas of the left hand tubes while not increasing their aggregate cross sectional areas.

To be more specific, it will be seen from Fi 2 that the left hand group of tubes 21 col ectively occupy substantially as much of the cross sectional area of the boiler as a the combustion gases is also.

through the righthand tubes 19 (Fig. 2) are much hotter um e 01mm whole as do the right hand tubes 19. I have shown, for example, forty right hand tubes 19 of 3 outside diameter, and 52 left hand tubes 21 of 3" diameter. Standard tubes for fire tube boilers having 3 outside diameter have 2.78', inside diameter. Standard boiler tubes 3 outside diameter have inside diameter of 3.26". Tabulating this for convenient reference we have:

Left Right hand hand tubes 21 tubes 19 Outside diametor.

Inside diameter Inside ems-sectional area Aggregate inside cross-sectional area. Outside cimumiempno Aggregate outside circumferences i ws s From the above table we see that the aggregate inside cross sectional areas-the total area for thepassage of flue gases-for the left hand tubesis about ti less than that of the right hand tubes. I

Ive also see that the aggregate outer circumferences'-the heat transfer areas-of the left hand tubes is about 11%); more than that of the right hand tubes. (Of course, the aggregate circumferences of the tubes would have to bemultiplied by their lengths in order to give the true value of the heat transfer areas, but since I am discussing for the present the relation between the two sets of tubes were the tubes of the same length, it is obvious that it is not necessary to determine the exact area in order to determine the proportions-between the two total heat radiating areas.) The ti less and the 11 more, as taken from the above figures, means, in eflecnan advantage of about 18% in the relation which I have described between the two sets of tubes.

Now by making the left hand tubes 21 longer than the right hand tubes 19 I have, of course, greatly exaggerated that advantage. I can, therefore, securesuch an advanta e in any one of three ways. First, by usingdarger but fewer tubes on one side than on the other side, or secondby using the same number of tubes and same size of tubes on one side as on the other side, or third by combining the twoideas as I have shown specificall in the drawings. v

I hile the arrangement of fire tubes as thus far described is of itself a great advantage, its principal purpose is in serving to effect a more perfect circulation of the water in the boiler so that the volume of the boiler and the heat contact areas of the fire tubes can be utilized to the fullest extent.

As the fire tubes 19 are considerably hotter than the fire tubes 21, there is a higher temperature gradient between the former tubes and the working fluid than in the latter, producing increased heat transfer to the fluid,

' ca forward end ofthe boiler all ofthe, fire tubes hotter group of tubes, resulting in a boiling upof the water adjacent the right hand'tubes and its return to the base ofjtheboiler on the left hand side. I take advantage of this fact by placing a verticalbafilef25 along the I interior of the boiler between the two groups of fire tubes. This baflle 25 extends from the uppermost fire tubes to a point a sufiicient distance from the bottom of the'boiler or crownsheet 18 to permit a substantial volume of water flow across'the bottomof the boiler.

Instead of suspending the bafile f25' from cross-members resting on the uppermost-ad acent fire tubes, I prefer 1n newboiler'con struction to suspend them from the top of the boiler, by turn buckle rods'26 as shown in Figs. 1 and 2, thereby providing fort-he adjustment of the baffle tosuc'h level relative to the normal water level aswill most greatly aid increased circulation. I prefer to terminate the bafile-25 short of the front and back heads l l and 15 and's pace them from the headers by short horizontal strips extending from the end edges of the bafiie plate to the respective headers '14 and 15 as shown in I dotted l nes on Flgure 1 tofpermitsome c rculation of water across the ends of'the boiler; Battling of the battle against the 'ad acent fire tubes maybe precluded by the use of angle irons 27 or other spacers secured to'the sides of the baflle to hold it securely intermediate the fire tubes. l The greater tendency of the water tofiow upwardly on the right hand side across the a 'hot tubes 19 than'on the left hand side across the cooler tubes-21 results in a rotary circulation'of the water which iscounter-clockwise in Fig. 2 as indicatedby the arrows. his rotary circulation hasthe two-fold advantage of utilizing to the fullest. extentthe heat transfer areas of the the tubes and to prevent the accumulation of deposit inthe bottomof the boiler, that is on the crown. sheet-118.

In the preferred modification shown Figures 4: to 6 my invention is shown applied to'an existing boiler-structurel The shell of the boiler 10"' isin general cylindrical and is here shown without water legs'as, in the PIGVlOUSzI'IlOCllfiCZLtlOIl. 'At the extend from a' common front head 14c and in this modification the fire tubes are shown of equal length and equal size terminating in an auxiliary rear head 15 In order to provide for the direction of the heated gases successively throughthe two groups of tubes, the structure supporting and enclosing the rear end of the boiler may bechanged'toprovide for a gas chamber 28 in which the fire tubes 19 and 21 terminate. This gas chamber may be constructed of the usual masonry lined with fire brickand: is dividedat its upper end into two separate chambers by the water wall 29 which consists of arectangular water containerin open relation with the end of the boiler throughan openingmade in the rear head 15 between the ends of the groups of tubes to be segregated. The water wall. 29thus provides a'means for dividing thechamber 28 into two separate chambers with a relatively thin partition capable of attachment to the boiler between the ends of the tubes 19. and 21 and which will not burn out due-to the presence of circulating water in its interior. i i v i In operation, thereforey the combustion i gases pass over the bridge wall l7 around the rear end of the ground sheet l8 into the left band (Fig. 5) portion 28 of the chamber 28,:forwardly through the fire tubes 19" on the right'side of the boiler into the forward smoke box crossing over to the left and passing rearwardly through the left side fire tubes 2? into the rear smoke box 28 thence upwardly vthroughthe stack 24*. Thus the heated gases are first directed through the tubeson one side of the boiler andthence re-. turned through the tubes on the-other side, with the same results previously described in Figs. 1 to 3. i

i Provision'may also be made in this modification, if desired; for a rear smoke b02128" -which is offset downwardly in reference to the fire tubes 21 for the purpose of drawing the combustion gases downwardly aud opposing the tendency of combustion gases to pass through only the uppermost tubes'of the group.

For the same purpose as in the previous modification my improved boiler here is provided with a water bafile 25 extending in the interior of the boiler from the uppermost fire tubes to-a point a sufiicient distance from the bottom of the ground sheet 18 to permit a substantial volume ofwater to flow across the bottom of the boiler. This bafile may be made adjustable as in Figs. 1 to 3 but in applying my invention to existing boiler structures, I

prefer tosuspend the baffle 25 -from two or more cross'members 29 thereby supporting the baffle without further modification of the boiler to insert supportingrods. Rattling'of the bafiie against adjacent fire tubes is here likewise precluded by the use of angleirons 27 or other spacers secured to the' sides of the bafile to hold it securel-yintermediate the fire tubes. tion which may bereadily applied to exist- I have thus provided my invent llO ing boilers and which will result in a rapid, circulation of the water (counter-clockwise the other.

& 1,779,9s9

as viewed from the front of the boiler), giving increased efiiciency of operation and preventing theaccumulation of deposit in the bottom of the boiler. This circulation is fur.-

' ther substantially aided by the cross section of the boiler being circular.

While I have described this particular embodiment of my invention in this particular type of boiler, I contemplate that many changes may be made therein without departing from the spirit or scope of my invention.

I claim 1. The combination with a cylindrical boiler having a multiplicity of longitudinal fire tubes, of means dividing the tubes vertically into right and left groups and sending the combustion gases therethroughin series, and a bafile in the water compartment and between the groups of fire tubes for giving the watery a rotary circulation upwardly through one group and downwardly through 2. The combination with a horizontal boiler having a multiplicity of longitudinal fire tubes, of means for dividing the tubes vertically into right and left groups and sending the combustion gases therethrough in series, whereby .there will be temperature difference betweenthe groups, and a bafile in the water compartment and between the groups of tubes for confining the water, set in motion by temperature difference between the gases, to a rotary circulation. 1

3. The combination with a boiler having a multiplicity of longitudinal fire tubes divided vertically into a right and a left group, of passage means for the combustion gases directing them through the respective groups of fire tubes in series, and a vertical bafile plate positioned longitudinally of the'boiler and between the two groups of fire tubes but permitting the flow of water across the bottom and top of the boiler.

4. The combination with a boiler having longitudinal fire tubes therethrough divided "ertically intogroups and connected in series as regards the passage of combustion gases, of means for pulling the combustion gases down into the lower tubes of the posterior group comprising a discharge opening connecting with the stack end of the posterior group, the upper margin of said opening being below the upper tubes of the posterior group but above the lower tubes thereof.

5. The combination with a boiler having longitudinal fire tubes therethrough divided vertically into groups and connected in series as regards the passage of combustion gases, of means for pulling the combustion gases down into the lower tubes of the posterior group comprising'a discharge opening connecting with the stack end of the posterior group, the upper margin of said opening bemg below the upper'tubes'of the posterior group, comprising a rear smoke box having a discharge opening offset downwardly relatively to the tubes of the posterior group.

6. The method of effecting an improved circulation in a boiler having horizontal tubes, which consists in heating the fire tubes on one side of the boiler to a higher temperature than those on the other side, and confining the cross flow intermediate the ends of the boiler to paths above and below the fire tubes. I

7. The combination with a cylindrical I boiler having horizontal fire tubes, of a vertical 'baflie extending longiutdinally of the boiler and dividing the tubes into two groups but permitting water flow beyond the upper and lower edges of the bafile, and means for heating the fire tubes of one group to a higher temperature than those of the other group whereby water will flow upwardl over the hotter tubes across the upper e ge of the baflie downwardly across the lower tubes and beneath the lower edge of the bafile.

8. The combination with a circular boiler of a vertical bafiie plate extending lon itudinally thereof and providing room a ove and below its edges for the circulation of the water, of a first group of longitudinal fire tubes disposed on one side of the baflie and a second group of longitudinal fire tubes disposed on the other side of the baflie,and means for conducting the combustion gases through the two roups of fire tubes in series, first through t e said first group of fire tubes and then throu h the said second group of fire tubes, the. re tubes of the first group bein larger in diameter than those of the second group but fewer in number so that the proportion of the aggregate cross sectional areas to the a gregate circumferences of the posterior tu es greater than that in the anterior tubes.

9. The combination with a boiler having a multiplicity of fire tubes arranged in two groups, of means for passing the combustion gases through the two groups of fire tubes in series, the fire tubes of the anterior group being fewer in number than those of the posterior group but larger in diameter, whereby the ratio of the aggregate cross-sectional areas of the fire tubes of the anterior group to that of the posterior group is considerably greater than the ratio of the aggregate perimeters of the fire tubes of the anterior group to that of the posterior group, the arrangement of said groups being such as to produce a thermo siphon circulation of water up through one group of tubes and down through the other.

In witness whereof, I hereunto subscribe my name this th day of August, 1926.

PAUL G. KAISER. 

